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EP 0 123 717 B1 |
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EUROPEAN PATENT SPECIFICATION |
(45) |
Mention of the grant of the patent: |
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20.04.1988 Bulletin 1988/16 |
(22) |
Date of filing: 27.07.1983 |
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International Patent Classification (IPC)4: B25C 1/08 |
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(54) |
Portable gas-powered fastener driving tool
Tragbares, gasbetätigtes Befestigungswerkzeug
Outil portable de fixation entraîné par gaz
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Designated Contracting States: |
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DE FR GB IT |
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Priority: |
02.05.1983 US 490408
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Date of publication of application: |
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07.11.1984 Bulletin 1984/45 |
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Proprietor: SIGNODE CORPORATION |
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Glenview
Illinois 60025 (US) |
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Inventor: |
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- Wagdy, Mohamed K.
Desplaines
Illinois 60018 (US)
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(74) |
Representative: Groening, Hans Wilhelm, Dipl.-Ing. |
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Strehl Schübel-Hopf Groening & Partner
Postfach 22 14 55 80504 München 80504 München (DE) |
(56) |
References cited: :
EP-A- 0 056 989 US-A- 3 815 566 US-A- 4 040 554
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EP-A- 0 056 990 US-A- 3 893 479 US-A- 4 200 213
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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[0001] This invention relates generally to fastener driving tools of the type used to drive
staples, nails, etc. into a workpiece and in particular to such a tool powered by
the forces generated in a combustion chamber.
Background of the Invention
[0002] There is a need to have a portable tool capable of generating high forces to drive
fasteners such as a 3) inch long nail. The current prevalent tool for driving such
fasteners requires a continuous source of pressurized air. There have been attempts
at developing portable tools using internal combustion principles such as those illustrated
in US-A-3,042,008 and 4,200,213 and US-A-3,967,771. In addition to those patents it
is to be noted that the assignee of the present invention has made a significant development
in this area as covered by two patent applications with priority of January 22,1981
in the name of M. Nikolich entitled "Combustion .Gas Powered Fastener Driving Tool",
EP-A-056 990 and "Portable Gas-Powered Tool With Linear Motor", EP-A-056 989 both
of which are assigned to the assignee of the present invention. The tools shown in
these applications will be referred to herein since a number of the features covered
in the instant application are improvements over such tools.
[0003] It is to be noted that some of the basic concepts employed in the tools illustrated
in the aforementioned Nikolich applications are incorporated in the tools illustrated
herein. While sufficient details will be set forth herein for an understanding of
the present invention, if further information is desired reference may be made to
these applications. It is to be noted that the tools disclosed in the aforementioned
Nikolich applications are believed to be totally satisfactory and that as in all such
developments improvements are continuously being made to increase the efficiency and
operability of such tools and it is in these areas that the instant application is
directed.
Summary of the Invention
[0004] The present invention relates to an improved fastener driving tool powered by the
gases produced from the combustion of a fuel and air mixture within a confined space.
The instant tool contains a number of features which adds to the efficiency of the
tool by way of providing a mechanism for controlling the opening and closing of the
combination chamber in conjunction with the bottom trip mechanism which prevents inadvertent
operation of the tool unless it is in engagement with the workpiece. This is accomplished
by providing a sleeve valve that is controlled by the operation of the bottom trip
mechanism, which sleeve valve acts to open or close the combustion chamber ports through
which air is introduced and spent combustion gases are scavenged. During the operation
of the tool the spent combustion gases are allowed to escape through a check valve
located in the side wall of the piston cylinder adjacent a bumper located at the bottom
of the cylinder in which the drive piston is located. A partial vacuum is momentarily
maintained in the combustion chamber to permit atmospheric air disposed below the
driven piston to positively return the piston to its driving position.
[0005] In addition there is provided a novel metering valve arrangement operated by the
valve sleeve and an interlock mechanism which prevents actuation of the fan in the
combustion chamber in the event the magazine is inadvertently disconnected.
[0006] Essentially, when a fastener is to be driven the combustion chamber is closed off
by the movement of a slidable sleeve through the action of a work sensitive probe
member that is engaged when the tool is moved into contact with the workpiece into
which the fastener is to be driven. The closing of the chamber by the slidable sleeve
also acts to introduce fuel into the combustion chamber. Movement of the slidable
sleeve to close the combustion chamber permits the trigger to be moved to operate
the tool. Pulling of the trigger acts to generate a spark in the combustion chamber
and prior thereto the fan in the combustion chamber is turned on. This sequence of
events occurs substantially simultaneously with the result that combustion occurs
and the force generated moves the piston to drive a fastener into a workpiece.
[0007] Shortly before the piston reaches the bottom of its driving stroke where it contacts
a resilient bumper the piston passes valved ports in the piston cylinder wall above
the bottom of the piston cylinder to exhaust gases from the combustion chamber. These
ports help facilitate removal of the combustion gases to aid in the partial vacuum
being set up so that atmospheric air beneath the piston after passing the cylinder
ports is more effective to return the piston to its driving position. The above actions
take place very quickly and thereafter when the trigger is released and the tool is
removed from the work- piece the combustion chamber is opened to bring about further
expunging of the spent gases from the chamber and fresh air is admitted for a subsequent
cycle. A trigger interlock mechanism includes a cam arrangement which serves to retain
the slidable cylinder in the closed position until the trigger is released. When the
trigger is released the slidable valve sleeve is returned to open the combustion chamber
ports by the action of a compression spring that acts to. move the work sensitive
probe assembly outwardly relative to the nose of the tool in which position it will
prevent subsequent actuation of the tool until the workpiece is again contacted.
[0008] In the following description of the drawings the features unique to the improved
tool are disclosed and will be described in detail and general reference will be made
to other components of the tool to understand the operation thereof. For further details
of a similar tool reference is again made to the Nikolich applications EP-A-056 989
and EP-A-056 990 with the priority of January 22,1981.
Brief Description of the Drawings
[0009]
Figure 1 is a partial cross-sectional, side elevational view of a fastener driving
tool illustrating the relative position of the principal components prior to firing;
Figure 2 is a view similar to Figure 1 but with the tool in contact with the workpiece
and illustrating the piston in both the driving and driven positions;
Figure 3 is an enlarged view showing the metering valve in the closed position;
Figure 4 is an enlarged view showing the metering valve opened by the upward movement
of the valve sleeve;
Figure 5 is a partial enlarged view showing the piston in its driven position; and
Figure 6 is a view similar to Figure 5 with the piston returning to its driving position;
and
Figure 7 is a view taken along line 7-7 of Figure 2.
Detailed Description
[0010] Figure 1 illustrates a fastener driving tool 10 the principal components of which
are attached to or carried by a generally hollow housing 11. The housing 11 of the
tool 10 has three major sections: a barrel section 14; a graspable elongated handle
section 15 extending horizontally outwardly from a position generally midway of the
barrel section; and a base 13 extending under the barrel section and the handle section.
Included in the base 13 is a magazine assembly 16 holding a row of nails 17 disposed
transversely to the path of a fastener driver 20 and a battery pack (not shown) for
the fan motor to be later discussed. The lower end of the barrel section 14 carries
a guide assembly 22 which guides the fastener driver and associated fastener towards
the work- piece. The magazine 16 supplies fasteners serially under the fastener driver
20 into the guide assembly 22 to be driven into the workpiece. The details of the
magazine assembly are not important to an understanding of the present invention.
[0011] A fuel tank 24 is mounted between the barrel section 14 and the handle section 15
of the housing 11. The fuel tank 24 is filled with a liquified combustible gas kept
under pressure, such as MAPP gas, or propane or butane, which vaporizes when it is
discharged to the combustion chamber. The upper end of the fuel tank 24 carries a
fuel valve 26 for metering fuel out of the tank.
[0012] Located adjacent the valve 26 for controlling the opening and closing of the fuel
valve is a valve actuator assembly 27, the operation of which will be described in
detail hereinafter. Essentially, operation of the fuel valve assembly 26 introduces
a metered amount of fuel into the combustion chamber. There is also provided a cap
28 which can be removed to replace the fuel tank 24.
[0013] At the interior of the lower end of the barrel section 14 of the housing 11 there
is located the main cylinder 29 within which the driving piston 30 is mounted. The
piston carries the upper end of the fastener driver 20. The upper end of the barrel
section 14 of the housing 11 contains an electrically powered fan 32 for providing
turbulence in the combustion chamber prior to ignition of fuel- air mixture disposed
therein. The combustion chamber 39 within which the fan 32 is located is defined by
the cylinder 35, cylinder head 38 and piston 30. The cylinder 35 in the illustrated
embodiment is formed as an upper extension of cylinder 29 and defines ports 36 that
are open or closed to atmosphere depending on the position of sleeve valve 33. As
shown in Figure 1 ports 34 of sleeve 33 are in alignment with ports 36 to admit air
to combustion chamber 39 whereas in Figure 2 where combustion has occurred the ports
34,36 are out of alignment and the combustion chamber 39 has been sealed off from
the atmosphere. The operation of the sleeve valve will be discussed hereinafter.
[0014] The lower end of the cylinder 29 is open to the atmosphere and has disposed therein
an annular bumper 40 which serves as a shock absorber for the piston 30 at the bottom
of its travel (see Figure 5). Located above the lower end of the bumper 40 are a plurality
of ports 42. The piston 30 moves between the upper end of the cylinder 29 and the
lower end as shown in Figure 5 carrying with it the fastener driver 20 which slidably
moves through the guide assembly 22. As illustrated in the drawings, the piston is
frictionally engaged with the sidewalls of the cylinder 29 by sealing means 46 comprising
an o-ring disposed between the outside periphery of the piston 30 and the inside sidewalls
of the main cylinder 29. The o-ring is sized so that the frictional force between
the piston 30 and the inside sidewalls of the main cylinder 29 is sufficiently great
that in the absence of a differential pressure across the piston, the piston will
remain fixed in place relative to the interior sidewalls of the main cylinder. The
relationship is required so that when the piston is returned to its driving position
it will remain in this position until the tool is again fired. It is to be noted that
when the tool is not being operated the piston 30 shown in Figure 1 will move slightly
downward to where the o-ring 46 will frictionally engage the inside sidewall of cylinder
29 and remain positioned in the driving position.
[0015] It is to be noted that the ports 42 are normally closed off from atmosphere by flap
valves 43 which are supported in their open position by a ring 44. During the driving
of the piston the air under the piston will be evacuated to atmosphere through the
bottom of the cylinder 29 with the ports 42 remaining closed. After the system 30
passes the ports 42 the combustion gasses located above the piston will open to valves
43 to assist in the evacuating of the combustion gasses to help provide a vacuum in
the expanded combustion chamber resulting from the downward movement of the piston
30 (see Figure 5).
[0016] As previously mentioned the movement of the sleeve valve 33 that is slidably disposed
relative to the cylinder 35 controls the opening and closing of the combustion chamber
39. When the sleeve 33 is in its upper position it closes off the combustion chamber
39 from atmosphere (see Figure 2). When lowered as shown in Figure 1 the sleeve 33
permits expunging of the combustion gases as well as the reintroduction of fresh air
into the combustion chamber. It can be seen that in the position shown in Figure 1
the combustion chamber is open to atmosphere both above and below the fan 32.
[0017] The movement of the sleeve valve 33 is affected by a work sensitive probe assembly
50 that functions to move the sleeve valve 33 to close the combustion chamber and
permit operation of the tool in the manner to be described hereinafter when it is
brought into contact with the workpiece into which a fastener is to be driven. In
the embodiment illustrated the mechanism interconnecting the work sensitive probe
sleeve 52 and link 54 to the sleeve 33 includes a member 56 biased outwardly by spring
57 in chamber 58. Connected to member 56 is a set of lifting rods 60 that are connected
to the slidable sleeve 33 and when moved function to raise and lower the sleeve 33.
Specifically, connected to the member 56 are four rods, the upper ends of which extend
into through openings 47 in the sleeve 33 and are retained therein by rings 48. Thus,
contact of the sleeve 52 with the workpiece will result in the combustion chamber
being closed and will permit operation of the tool as described hereinafter.
[0018] All the major components fitting within the barrel section 14 of the housing 11 have
been described with the exception of those components that are joined to the cylinder
head 38.
[0019] The cylinder head 38 carries the electric fan 32, spark plug 63 and provides an internal
passageway 64 through which fuel is injected into the combustion chamber 39.
[0020] Referring now to Figures 3 and 4 there is illustrated the mechanism for operating
the fuel metering valve. It can be appreciated that the prescribed amount of fuel
is to be introduced into the combustion chamber 39 after the chamber is filled with
air and has been sealed off from the atmosphere. To this end, the control of the fuel
valve 26 is effected by the movement of the sleeve valve 33. Specifically the fuel
valve is opened to admit a quantity of fuel through the passageway 64 to the combustion
chamber 39 by a wedge shaped portion 33A of the sleeve 33 which portion 33A biases
the valve actuator 65 to the right against the action of the spring 67 located between
the cylinder head 38 and a ring 66 secured to the actuator 65. This mode of operation
occurs after the sleeve 33 has been moved upwardly an amount sufficient to seal the
combustion chamber 39 (see Figure 4).
[0021] Located in the handle 15 of the housing 11 are the controls for operating the tool
10. This includes a switch 75, a trigger mechanism 76, a piezo-electric firing circuit
77 which activates the spark plug 63 and a cam interlock mechanism 80 the operation
of which controls the actuation of the trigger. The switch 75 is operated when the
operator grips the handle of the tool and contacts the pivoted lever 82 which makes
contact with the switch 75. The electrical contact assembly is joined in series with
the battery pack located in the base of the magazine assembly and with the switch
84 connected to complementary portions of the magazine assembly 16 and the main housing
11. When the magazine is in spaced relation to the housing the fan circuit is broken
and cannot be activated. Contact with the switch 75 actuates the electric fan so that
it is turned on the moment the fastener tool is gripped.
[0022] As previously mentioned, the trigger cannot be operated until the cam interlock assembly
80 is free to move. Movement of the cam interlock assembly is normally prevented from
being moved by a U-shaped trigger rod mechanism 90 (see Figure 7) that is secured
to the sleeve 33. As shown in Figure 1 when the work sensitive probe assembly 50 is
in the extended position the U-shaped rod 90 is located immediately adjacent the generally
triangular shaped cam member 92. The trigger 76 is associated with a pin 94 extending
from one end of the triangular cam 92 which cam is pivotally mounted relative to the
housing by pivot 96. The pin 94 is located in an elongated slot 98 found in the trigger
bracket 100 which facilitates upward movement of the trigger bracket while causing
pivotal movement of the cam member 92. Thus as shown in Figure 1 the trigger 76 cannot
be moved upwardly to activate the piezo-electric system 77 until the U-shaped rod
90 located adjacent the cam 92 has been moved out of abutting relationship therewith.
Disengagement of the rod 90 from cam 92 will occur upon upper movement of the sleeve
33 resulting from the upward movement of the work probe assembly resulting when it
contacts a workpiece.
[0023] Referring to Figure 2 it is shown that the slidable sleeve 33 has been moved to close
off the combustion chamber in which position the U-shaped rod 90 has been moved free
of the cam and thus the trigger can be moved upwardly to pivot the cam 92 about its
pivot pin 96. During this motion the pin 94 secured to the cam which fits in the slot
98 of the trigger moves to the lower end of the slot 98 in the manner shown in Figure
2. Thus it can be seen that the tool can be fired when the workpiece has been engaged
and the trigger rod 90 is removed from adjacent the cam. It remains to note that the
configuration of the cam 92 is such that the rod 90 cannot descend to permit opening
of the combustion chamber by downward movement of the slidable cylinder if the trigger
is not released due to the rod 90 being blocked by the adjacent upper surface 102
of the cam 92. Thus the trigger must be released to permit the slidable sleeve to
move to open the combustion chamber to atmosphere. When the trigger is released to
the biasing force extended there-against by the piezo-electric member the cam 92 is
moved in a clockwise direction back to the position shown in Figure 1 to where the
sleeve 33 is free to move downwardly by the action of the spring 57 against the member
56. The rod 90 will then be lowered into the position shown in Figure 1 with the result
that the tool cannot be fired until the work sensitive probe assembly has been reenergized.
Tool Operation
[0024] Now that all the major components of the tool have been described in detail the integrated
operation of the various components of the tool will be described while highlighting
the remarkable manner in which the tool operates.
[0025] Referring to Figure 1, whenever the tool 10 is grasped about its handle the switch
75 is tripped which starts the electric fan 32. It is to be noted that this will occur
only if the magazine assembly is in its proper position relative to the housing so
that the switch 84 which is in series with the switch 75 is closed. As long as the
tool is held above the workpiece such that the link 54 is fully extended, the combustion
chamber remains open to the surrounding atmosphere through suitable openings in the
housing 14 due to the sleeve 33 being maintained in the combustion chamber open position
by the biasing spring 57. Since the electric fan 32 is running a differential pressure
is produced across the combustion chamber 39 and fresh air will be introduced into
the combustion chamber. The rotating fan blades produces a turbulent effect within
the combustion chamber 39.
[0026] Once the tool 10 is positioned in engagement with a workpiece the work sensitive
probe assembly 50 is moved inwardly. This action overcomes the biasing spring 57 and
forces the member 56 and associated lifting rods 60 upwardly which moves the sleeve
33 upwardly to close the combustion chamber. The upward movement of the sleeve 33
carries with it the rod 90 and thus moves it up out of contact with the cam 92 to
permit the trigger 76 to be fired. It is to be noted that as the sleeve 33 is moved
upwardly it engages the valve actuator 65 to open the fuel valve 26 to introduce a
metered amount of fuel into the combustion chamber. Movement of the trigger button
76 which is now possible since the rod 90 has been moved out of position trips the
piezo-electric firing circuit 77 which fires the spark plug in the combustion chamber.
The explosive gases moves the piston 30 downwardly to drive a fastener into the workpiece.
The piston moves downwardly to its driven position past the ports 42 and engages the
bumper 40. During the piston travel the air under the piston is forced outwardly through
the open bottom of the cylinder 29. When the piston passes the ports 42 the combustion
gasses above the piston flow out through ports 42. This venting assists in creating
a partial vacuum in the combustion chamber. This all occurs very quickly and the partial
vacuum is not instantly relieved since even though the tool may be immediately removed
from the workpiece the trigger has not been released and the sleeve valve 33 cannot
move down to open the combustion chamber. The partial vacuum combined with the atmospheric
air under the piston acts to return the driven piston back to its driving position.
When the piston is returned to the driving position it is retained in frictional contact
with the upper portion of the cylinder. This all happens very quickly and thus will
occur before the trigger is released. When the trigger is released it is biased outwardly
by the force exerted through the piezo-electric system 77. Movement of the trigger
rotates the cam 92 in a clockwise direction to the position shown in Figure 1 at which
time the sleeve valve 33 will be free to move downwardly through the action of spring
57 to open the combustion chamber to atmosphere to permit scavenging of the combustion
chamber through the action of the fan.
[0027] It is intended to cover by the appendant claims all such modifications which fall
within the scope of the invention. For example, while a sleeve valve has been illustrated
as a means for controlling the opening and closing of the combustion chamber other
slidable members actuated by the work sensitive probe assembly could be employed.
1. A portable fastener driving tool (10) comprising a housing (11), a main cylinder
(29) in said housing, a piston (30) in said main cylinder and movable from a driving
to a driven position, a driver (20) attached to said piston, a magazine (16) for supplying
fasteners (17) into position to be driven by said driver, a combustion chamber (39)
within said housing, having a wall portion (35) defining a plurality of openings (36)
and said piston as a wall portion thereof, a fan (32) in said combustion chamber and
controls (75) therefor to operate same to cause turbulence in said chamber (39), means
(33) for controlling the flow of gases into and out of said combustion chamber, a
work sensitive probe assembly (52, 54, 56) cooperating with said means (33) for controlling
the flow of gases whereby the combustion chamber is not closed off until the tool
is in position to drive a fastener into a work-piece, means (26) for providing fuel
into said combustion chamber and igniting (63) same for driving said piston to drive
a fastener and trigger operated means (80) responsive to movement of said means (33)
for controlling the flow of gases into and out of said combustion chamber whereby
the tool cannot be fired until the combustion chamber is closed and the chamber cannot
be opened until the trigger (76) is released, characterized in that the wall portion
(35) of the combustion chamber (39) is fixed relative to the housing (11) and said
means for controlling the flow of gases includes a slidable member (33) disposed adjacent
said openings (36), movable relative to said combustion chamber (39), and secured
to said probe assembly (52, 54).
2. A portable fastener driving tool as set forth in claim 1 in which the combustion
chamber wall portion (35) defining said openings (36) is cylindrical and the slidable
member (33) for controlling the flow through said openings is a sleeve member surrounding
said cylindrical wall portion that defines openings (34) adapted to be out of alignment
with said combustion chamber openings (36) when the tool is in engagement with the
workpiece and to open said combustion chamber (39) to atmosphere when the tool is
removed from the workpiece.
3. A portable fastener tool as set forth in claim 2 in which the means for providing
fuel to the combustion chamber includes a metering valve (26) controlled by a valve
actuator (65) and the sleeve member defines a portion (33A) adapted to engage said
valve actuator to open said metering valve to admit fuel to the combustion chamber
(39) when the combustion chamber has been closed off from the atmosphere.
4. A portable tool as set forth in claim 2 in which the bottom of the main cylinder
(29) is open to atmosphere and has disposed adjacent the bottom thereof a bumper (40)
for damping the action of the piston (30) at the end of its driving stroke, said main
cylinder (29) also defining a plurality of valved openings (42) adjacent said bumper
whereby when the driving piston passes said openings (42) the combustion gases will
flow out through said valved openings to vent the combustion gases and thus facilitate
the return of the piston to its driving position resulting from the differential pressure
between the atmospheric pressure below the piston and the partial vacuum occurring
in the combustion chamber (39) after combustion occurs.
1. Tragbares Eintreibgerät (10) für Befestigungsmittel, bestehend aus einem Gehäuse
(11), einem Hauptzylinder (29) in dem Gehäuse, einem Kolben (30) in dem Hauptzylinder
und zwischen einer treibenden und angetriebenen Stellung bewegbar, einem Treiber (20),
der an dem Kolben befestigt ist, einem Magazin (16) zum Zuführen der Befestigungsmittel
(17) in die von dem Treiber einzutreibende Stellung, einer Verbrennungskammer (39)
innerhalb des Gehäuses, mit einem Wandteil (35) mit mehreren Öffnungen (36) und dem
Kolben als einem Wandteil desselben, einem Ventilator (32) in der Verbrennungskammer
und Steuermitteln (75) für diesen zum Betätigen desselben zum Hervorrufen einer Turbulenz
in der Kammer (39), Mitteln (33) zum Regeln des Gasstromes in und aus der Verbrennungskammer,
einer auf das Werkstück ansprechenden Fühlvorrichtung (52, 54, 56), die mit dem Mittel
(33) zum Regeln des Gasstromes zusammenwirkt, wodurch die Verbrennungskammer nicht
verschlossen wird, bis das Gerät sich in der Stellung zum Eintreiben eines Befestigungsmittels
in ein Werkstück befindet, Mitteln (26) zum Zuführen von Brennstoff in die Verbrennungskammer
und zum Zünden (63) desselben zum Antreiben des Kolbens im Sinne eines Eintreibens
eines Befestigungsmittels und schalterbetätigten Mitteln (80), die auf die Bewegung
der Mittel (33) zum Regeln des Gasstromes in und aus der Verbrennungskammer ansprechen,
wodurch das Gerät nicht betätigt werden kann, bis die Verbrennungskammer geschlossen
ist und die Kammer nicht geöffnet werden kann, bis der Schalter (76) freigegeben ist,
dadurch gekennzeichnet, daß der Wandteil (35) der Verbrennungskammer (39) in bezug
auf das Gehäuse (11) fest angeordnet ist, und daß die Mittel zum Regeln des Gasstromes
ein verschiebbares Organ (33) umfassen, das in der Nähe der Öffnungen (36) angeordnet
ist und in bezug auf die Verbrennungskammer (39) relativ bewegbar sowie mit der Fühlvorrichtung
(52, 54) fest verbunden ist.
2. Tragbares Eintreibgerät für Befestigungsmittel nach Anspruch 1, dadurch gekennzeichnet,
daß der Öffnungen (36) aufweisende Wandteil (35) der Verbrennungskammer zylindrisch
ist und das verschiebbare Organ (33) zum Regeln der Strömung durch die Öffnungen aus
einer den zylindrischen Wandteil umgebenden Hülse besteht, die Öffnungen (34) aufweist,
die sich außerhalb der Ausrichtung gegenüber den Öffnungen (36) der Verbrennungskammer
befinden, wenn das Gerät an das Werkstück angelegt ist, und zur Öffnung der Verbrennungskammer
(39) zur Atmosphäre hin dienen, wenn das Gerät von dem Werkstück entfernt ist.
3. Tragbares Gerät für Befestigungsmittel nach Anspruch 2, dadurch gekennzeichnet,
daß die Mittel zum Zuführen des Brennstoffs zur Verbrennungskammer ein Dosierventil
(26) umfassen, das von einem Ventilbetätiger (65) gesteuert wird, und die Hülse einen
Teil (33A) aufweist, der zur Anlage an dem Ventilbetätiger im Sinne der Öffnung des
Dosierventils dient, um Brennstoff in die Verbrennungskammer (39) zuzulassen, wenn
die Verbrennungskammer gegenüber der Atmosphäre verschlossen worden ist.
4. Tragbares Gerät nach Anspruch 2, dadurch gekennzeichnet, daß der Boden des Hauptzylinders
(29) zur Atmosphäre offen ist und in der Nähe seines Bodens einen Dämpfer (40) zum
Dämpfen der Wirkung des Kolbens (30) am Ende seines Treibhubes angeordnet ist, daß
der Hauptzylinder (29) eine Mehrzahl von als Ventil wirkenden Öffnungen (42) in der
Nähe des Dämpfers aufweist, wodurch, wenn der Treibkolben an den Öffnungen (42) vorbeibewegt
wird, die Verbrennungsgase durch die als Ventil wirkenden Öffnungen ausströmen, um
die Verbrennungsgase abzulassen und somit die Rückkehr des Kolbens in seine Treibstellung
als Ergebnis des Differentialdrucks zwischen dem atmosphärischen Druck unterhalb des
Kolbens und dem partiellen, in der Verbrennungskammer (39) im Anschluß an die Verbrennung
auftretenden Vakuum in der Verbrennungskammer (39) zu erleichtern.
1. Outil portatif pour enfoncer des organes de fixation (10), comprenant un corps
(11 un cylindre principal (29) contenu dans ledit corps, un piston (30) contenu dans
ledit cylindre principal et qui peut se déplacer d'une position d'attaque à une position
repousée, un poussoir (20) fixé audit piston, un magasin (16) servant à acheminer
des organes de fixation (17) en bonne position pour être enfoncés par ledit poussoir,
une chambre de combustion (39) formée dans ledit corps et possédant une partie de
paroi (35) qui définit une pluralité d'ouvertures (36), ledit piston formant une autre
partie de sa paroi, un ventilateur (32) contenu dans ladite chambre de combustion,
et des commandes (75) servant à mettre ce ventilateur en action pour engendrer une
turbulence dans ladite chambre (39), des moyens (33) servant à commander la circulation
des gaz qui pénètrent dans ladite chambre de combustion et en sortent, un ensemble
sonde sensible à la pièce (52, 55, 56) qui coopère avec lesdits moyens (33) pour commander
la circulation des gaz, de sorte que la chambre de combustion n'est pas fermée avant
que l'outil ne soit en position pour enfoncer un organe de fixation dans une pièce,
des moyens (26) servant à introduire un carburant dans ladite chambre de combustion
et à mettre ce carburant à feu (63) pour repousser ledit piston de façon à enfoncer
un organe de fixation, et des moyens (80) actionnés par une gâchette, qui répondent
à un mouvement desdits moyens (33) servant à commander la circulation des gaz qui
pénètrent dans ladite chambre de combustion et en sortent, de sorte que l'outil ne
peut pas être tiré avant que la chambre de combustion n'ait été fermée, et de sorte
que la chambre ne peut pas être ouverte avant que la gâchette (76) ne soit relâchée,
caractérisé en ce que la partie de paroi (35) de la chambre de combustion (39) est
fixe par rapport au corps (11), et en ce que les moyens servant à commander la circulation
des gaz comprennent un élément coulissant (33) disposé adjacent aux- dites ouvertures
(36) et qui peut se déplacer par rapport à ladite chambre de combustion (39) et est
solidaire dudit ensemble sonde (52, 54).
2. Outil portatif pour enfoncer des organes de fixation selon la revendication 1,
dans lequel la partie de paroi (35) de la chambre de combustion qui définit lesdites
ouvertures (36) est cylindrique, et en ce que l'élément coulissant (33) servant à
commander la circulation à travers lesdites ouvertures est un manchon qui entoure
ladite partie de paroi cylindrique et qui définit des ouvertures (34) adaptées pour
se placer hors d'alignement avec lesdites ouvertures (36) de la chambre de combustion
lorsque l'outil est en contact avec la pièce, et pour ouvrir ladite chambre de combustion
(39) sur l'atmosphère lorsque l'outil est écarté de la pièce.
3. Outil portatif pour enfoncer des organes de fixation selon la revendication 2,
dans lequel les moyens servant à introduire le carburant dans la chambre de combustion
comprennent une soupape doseuse (26) commandée par un actionneur de soupape (65),
et l'élément manchon définit une partie (33A) adaptée pour attaquer ledit actionneur
de soupape pour ouvrir ladite soupape doseuse afin d'admettre le carburant dans la
chambre de combustion (39) lorsque la chambre de combustion a été isolée de l'atmosphère.
4. Outil portatif pour enfoncer des organes de fixation selon la revendication 2,
dans lequel le fond du cylindre principal (29) est ouvert à l'atmosphère et présente,
adjacent à ce fond, un tampon (40) destiné à amortir l'action du piston (30) à la
fin de sa course motrice, ledit cylindre principal (29) définissant également une
pluralité de lumières obturables (42) adjacentes audit tampon, de sorte que, lorsque
le piston moteur passe au droit desdites lumières (42), les gaz de combustion s'écoulent
à travers lesdites lumières obturables pour éjecter les gaz de combustion, et faciliter
ainsi le retour du piston à sa position d'attaque sous l'effet de la différence de
pression existant entre la pression atmosphérique qui règne au-dessus du piston et
le vide partiel qui règne dans la chambre de combustion (39) après que la combustion
a été exécutée.